LOS ANGELES--US police on Saturday worked to identify bones and a personal document found in the remote desert region of Death Valley, California that may be linked to four German tourists who disappeared 13 years ago.

The Inyo County Sheriff's Department, the local coroner and the National Park Service said they had enough clues already to make the potential link to the group, last seen in the area in June 1996.

"Located close in proximity to the area where the skeletal remains were discovered was personal identification for one of the missing German tourists," said under-sheriff Jim Jones in a statement Friday.

Two months after they went missing, the tourist's rented van was discovered by investigators, but exhaustive searches of the area some 185 miles (300 kilometers) north of Los Angeles, on the border with Nevada, failed to turn up any evidence of their whereabouts.

The Los Angeles Times identified the group, all from Dresden, as 28-year-old Cornelia Meyer, her son Max, aged four, and 33-year-old man Egbert Rimkus and his son Georg Weber, 10.

Temperatures in sweltering Death Valley, one of the world's hottest and driest regions, would have been reaching a peak of about 115 degrees Fahrenheit (46 degrees Celsius) at the time of the group's disappearance.

When their vehicle was found, all four tires were flat, according to the Times, and investigators at the time believed the group had driven on the shredded wheels for two miles before stopping.